4 tablespoons salted butter, at room temperature
1 small shallot, peeled and finely chopped
1 large clove garlic, peeled and minced
8 ounces white or brown mushrooms, cleaned, stemmed and sliced ¼-inch thick
2 teaspoons sherry vinegar or red-wine vinegar
2 teaspoons finely chopped fresh thyme
Salt and freshly ground black pepper
1 baguette, cut crosswise into 4 (6-inch-wide) pieces
6 ounces Camembert, sliced ¼-inch thick
8 ounces Comte, coarsely grated (or use Gruyere, Swiss or Fontina)
Melt 2 tablespoons butter in a large nonstick skillet over medium-high heat. Add the shallot, and cook just until soft, about 5 minutes. Add the garlic, and cook for 1 minute. Add the mushrooms, and cook until soft, about 5 minutes.
Turn the heat to high, and add the vinegar. Cook until almost all of the vinegar has boiled away and the mushrooms have begun to caramelize around the edges, 1 to 2 minutes. Add the thyme and salt and pepper to taste. Stir once or twice, and remove from the heat. Transfer the mushrooms to a plate, and set aside. Wipe out the skillet with a paper towel.
Melt the remaining 2 tablespoons butter in a small pan or the microwave. Cut each baguette piece in half lengthwise. Pinch out a small amount of the soft center of each piece of bread to create a well. Place the baguette pieces, crust side up, on your work surface, and spread with the melted butter. Turn the bottom (flat) pieces crust side down. Distribute the mushroom mixture on the bread, followed by the Camembert and Comte. Place the remaining baguette on the top, crust side up.
Reheat the skillet over medium low heat for 2 minutes. Put the sandwiches in the pan, cover and cook for 5 to 6 minutes, until evenly browned. Turn the sandwiches, pressing each firmly with a spatula to compress the bread and filling. Cover and cook for 3 to 4 minutes, until the undersides are golden brown and the cheese has melted. Turn the sandwiches once more, press firmly with the spatula again, and cook for 1 minute, or until the cheese had completely melted. Remove from the pan, and let cool for 5 minutes. Cut in half, and serve.
"Grilled Cheese, Please" by Laura Werlin (Andrews McMeel, 2011)